March 01, 2012

Genetic affinities of Central Indian tribals

PLoS ONE 7(2): e32546. doi:10.1371/journal.pone.0032546

Genetic Affinities of the Central Indian Tribal Populations

Gunjan Sharma et al.

Abstract
Background

The central Indian state Madhya Pradesh is often called as ‘heart of India’ and has always been an important region functioning as a trinexus belt for three major language families (Indo-European, Dravidian and Austroasiatic). There are less detailed genetic studies on the populations inhabited in this region. Therefore, this study is an attempt for extensive characterization of genetic ancestries of three tribal populations, namely; Bharia, Bhil and Sahariya, inhabiting this region using haploid and diploid DNA markers.

Methodology/Principal Findings

Mitochondrial DNA analysis showed high diversity, including some of the older sublineages of M haplogroup and prominent R lineages in all the three tribes. Y-chromosomal biallelic markers revealed high frequency of Austroasiatic-specific M95-O2a haplogroup in Bharia and Sahariya, M82-H1a in Bhil and M17-R1a in Bhil and Sahariya. The results obtained by haploid as well as diploid genetic markers revealed strong genetic affinity of Bharia (a Dravidian speaking tribe) with the Austroasiatic (Munda) group. The gene flow from Austroasiatic group is further confirmed by their Y-STRs haplotype sharing analysis, where we determined their founder haplotype from the North Munda speaking tribe, while, autosomal analysis was largely in concordant with the haploid DNA results.

5 comments:

An interesting haplotype of R1a1a (M17) has been found in the paper of Gunjan Sharma et al., Genetic Affinities of the Central Indian Tribal Population, PLoS one, February 2012:DYS19=18DYS385=14-17DYS389=15-30DYS390=28DYS391=12DYS392=14DYS393=13DYS437=17DYS439=13DYS448=22DYS456=17DYS458=17

At first sight it could seem we have found the R-M420 not found so far in India with its DYS492=14, which presupposes a 13, whereas all the other R1a1a haplotypes have 11 or 10 and 12 from 11, but this haplotype has been tested for M17, then it isn’t an R-M420. Also the extremely large variance of the other markers makes us think that this value 14 derives from a modal 11 (or what was the modal at the origin of this subclade). Then again all the discourses about “modal” and “variance”, as I have supported many times, are worth nothing.But I think it would be something to say about the TMRCA of 10.97+/-1.86 kya (25 y for generation) even though calculated by the Zhivotovsky rate. It is clear that these R1a1a-s belong to different clades and the massive presence of the clade most usually found falsifies the calculation. It is clear that this haplotype is an outlier, but for this more interesting, because testifies all the mutation gone mostly for the tangent and not around the modal. If we calculate the intraclade between two of these haplotypes, for instance with this closer to the modal: 15, 11-14, 14-32, 24,10, 11, 12,14,10, 20, 15,16 we have 32 mutations. Also using the usual mutation rate of 0,0022, we have:(454x32)/28=518518x25=12,950and I have used a generation of 25 years and not 32 as I use usually, and I haven’t considered other mutations around the modal.

Conclusions? The ancientness of the haplogroups is much much more than it is usually thought.

This tends to disfavor the notion that tribals, at least in Central India, are really the oldest layer population genetically. As Indo-Europeans have clear and relatively recent orgins outside Central India, and the weight of the evidence favors the Munda as intrusive not all that much earlier (probably together with rice farming). Compared to these tribals, non-tribal Dravidians and non-tribals who are Indo-European language speakers seem to have a heavier share of haplotypes specific to India.

"This tends to disfavor the notion that tribals, at least in Central India, are really the oldest layer population genetically. As Indo-Europeans have clear and relatively recent orgins outside Central India, and the weight of the evidence favors the Munda as intrusive not all that much earlier"

I don't think it necessarily contradicts the notion concerning tribals. What it does do is show that later arriving haplogroups have been absorbed by the tribals and, in other cases, the tribals have been absorbed into the mainstream. Inother words the whole process has been far from simple.

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